Why doesn't the Graph Editor show my keyframes and connecting lines
The screen shot is a little low res, so it's hard to see.

Your keyframes in the dope sheet are in the 340 to 410 range but the graph editor is set to show the -200 to 200 frame range.

I think if you press the Home key while the cursor is in the graph editor the view should zoom to your keyframes.

Alternatively your keyframes are simply out of view on the y-axis of the graph editor and the Home will also solve this.